Improvement in the manufacture of iron and steel



UNITED STATES PATENT OEEIcE.

ROBERT MUSHET, OF OOLEFORD, ENGLAND.

IMPROVEMENT IN THE MANUFACTURE OF IRON AND STEEL.

Specification forming part of Letters Patent No. 17,389. dated May 26, 1857.

To all whom it may concern:

Be it known that I, ROBERT MUSHET, of Ooleford, in the county of Gloucester, metallurgist, a subject of the Queen ofGreat Britain, have invented Improvements in the Manufacture of Iron and Steel; and Ido hereby declare that the following is a full and exact description of my said invention.

\Vhen cast-iron has been purified or decarbonized by the action of air blown or forced into, through, or amongst its particles while it is in a molten or fluid state, it has been found that although the cast-iron is thereby nearly, it not wholly, decarbonized and purified from silicon or its oxide and some other matters, yet, nevertheless, it is difficult to convert it into iron or steel, and the ingots, articles, or pieces formed by pouring this purified iron into suitable molds, in some instances, prove to be incapable of extension by hammering or rolling at any temperature. In other instances they maybe extended into bars .by hammerin g or rolling; but the bars thus produced frequently have cracks or flaws along their edges, which unfit them for manufacturing purposes; and in other instances, though ingots of such purified iron may be extended by hammering or rolling into tolerably sound bars capable of being welded together, yet these bars are often found to be what is termed red-short or hot-short. They are also often characterized by being, when cold, ofa crystalline nature, and neither granular nor fibrous in their fracture. They are therefore what is termed coldshort-that is to say, brittle when cold. In gots thus castfrom purified iron are also generally porous and cellular in their structure, and when broken exhibit internally a multitude of small cavities, which not only increase the tendency of the ingots to crack when being rolled or hammered into bars, but they materially detract from the soundness or solidity of such bars, whether they be of iron or steel. For the purpose of remedying these defects in cast-iron purified by the action of a blast of air, and to convert it into malleable iron or steel, 1 add and combine with such purified iron, while in a melted state, a triple compound or material consisting of or containing iron, manganese, and carbon; and I vary or regulate the quantity or proportion of such triple compound or material for the purpose of obtaining one or other of those products-viz., malleable iron or steel. To the purified cast'iron, when it has become wholly decarbonized, or nearly so, by the action of air forced into it or among its particles, and while it is in a molten or fluid state, I add the triple compound, so that it may be mixed, al1oyed,or incorporated with the fluid purified iron; and this admixture I effect in any suitable furnace, vessel, or ladle, and then pour the mixtureinto suitable molds in any usual or convenient manner for producing castings, articles, ingots, or pieces of the desired forms or shapes. The proportion of the triple compound to be added to the purified cast-iron may be varied as circumstances may require-that is to say, according to the nature of the purified iron, the nature of the material containing iron, carbon, and manganese, and the effect intended to be produced.

In order to produce wrought-iron I add to the purified iron from about one-fiftieth part to about one thirty-third part, by weight, of the triple compound, or, in other words, from about two to three per cent-um of the triple compound.

To convert the decarbonized purified castiron into semi-steel I employ from about one thirty-third to about one-twentieth, in part, by weight, of the compound-that is to say, from about three to five per centum-and I use from about one-twentieth to about one-fifth part, by weight-that is to say, from about five to twenty per centum of the compound-when it is intended to convert the purified cast-iron into soft, medium, or hard steel. It will thus be understood that the softness or hardness of the steel may be regulated by diminishing or increasingthe quantity orproportion of the triple compound added to the purified decarbonized cast-iron.

The triple compound, or the material containing iron, carbon, and manganesepmay be conveniently and economically prepared by smelting into pi g-iron or cast-iron metal in the blast-furnace, with either coke, coal, or charcoal fuel, such sparry carbonates of iron termed spathose iron ores, or such other ores of iron as contain besides iron a considerable quantity of manganese; and I prefer to use the white crystalline cast-iron metal thus obtained, and known in Prussia as spiegeleisen, for this white cast-iron metal, while it contains a large alloy of manganese, is more free from sulphur, phosphorus, and silicon than the gray pig-iron obtained from smelting spathose manganesic iron ores; and I prefer to use such varieties of this whitecrystalline cast-iron metal as are found to contain a large alloy of manganese. Nevertheless, such triple compound or material of or containing iron, carbon, and manganese maybe produced in any other manner which may be found to be convenient and economical.

I noweproceed to describe the manner in which my invention may be practiced.

When the cast-iron to be operated upon has been so far purified in the purifying vessel or furnace-that is to say, the vessel or furnace in which the cast-iron is decarbonized by forcing airinto it while in a molten state-d tap it oft and allow it to flowinto a heated furnace, vessel, or ladle containing the requisite proportion of the triple compound, already heated or reduced to a molten or fluid state. The purified iron,t'alling into the furnace orvessel containing the fluid triple compound, will become mixed and incorporated therewith, and the resulting mixtureis then to be poured into molds in any usual or convenient mannerfor producing castings, articles, ingots, or pieces of the desired sizes, forms, and shapes; or the purified iron may be tapped into a heated furnace, vessel, or ladle, and the fluid triple compound poured upon it or into it; or the purified iron and the fluid triple compound or material may be poured into the heated furnace, vessel, or ladle simultaneously.

The triple compound of or containing iron, carbon, and manganese may be heated and rendered fluid in any convenientmanner, either in a crucible or in an air-furnace, a reverberatory furnace, or, in a common cupola melting-furnace, or otherwise; but when applying it in a heated state I prefer heating it when excluded as much as possible from contact with sulphury coke or other sulphury t'uel.

\Vhen the mixture of the triple compound with the purified iron is to be effected in ladles I use either fire-clay or black-lead crucibles for ladles, heated to a red or white heat, and held in a pair of pouring-tongs with double handles or otherwise, so that the heated crucibles containing the proper quantity of heated fluid compound may be held under the end of the spout or gutter, along which the purified iron flows from the purifying-vessel, and falling may be used, the interior of these ladles being vremelted, and I avoid as much as possibleany repeated rem'eltings of it. It may sometimes be necessary to accelerate the, mixture of the triple compound or material with the purified iron when combined in the same vessel, and

this may be done or promoted by stirring the fluid mass with an iron rabble, or preferably by introducing strips of well-dried wood and thrusting them down to the bottom of the metal, by which means a strong ebullition is at once excited.

Though I havein this specification described the addition of the triple compound or mate 1 rial of or containing iron, carbon, and manganese when heated so as to be in a molten or fluid state to cast-iron purified by air, nevertheless such triple compound or material may when heated, but not to such an extent as to become fluid, be added to the melted purified iron, or it may be added without having received a preparatory heating. In either of these cases it will be desirable to reduce the compound to small particles byany well-known granulating or pulverizing process, as in that its mixture with the molten metal will be greatly facilitated.

I prefer to operate upon purified and decarbonized iron which has been obtained from good pig-iron or other cast-iron of good quality as freeas possible from sulphur and phosphorus.

Having thus described the nature of my invention, I wish it to be understood that I claim- The addition of a triple compound or material of or containing iron, carbon, and manganese to cast-iron which has been purified and decarbonized by the action of air while in a molten or fluid state, or in any convenient manner so as to become mixed and combined in the process of manufacture, in order by the Witnesses:

THos. SMITH, Notary Public, Gloucester,

JOHN JONES, Consular Agent of United States, Gloucester. 

